Signaling system



Feb. 4, 1941,. c. J. FITCH SIGNALING SYSTEM Filed Nov. 1o, 19:58 s ysheets-sheet 1 b NN A @N @J \l r f| i QQ e ,WQ Nul \(N\ 9b TQQ WN n- .I+ 9% |L I .L www www ATTORNEY Feb; 4,

ci. J. FrrcH SIGNALING SYSTEM Filed Nov. io, 1958 l FIG. `3. 1

3 sheets-sheet 2 ,a/455 MANS/wwf@ y FIG. 2;

ATTORNEY Feb. 4, 1941.

Flae. FIG. 9.

FIG. Io. I\/ I FIG. II. H

FIG. I2. FIG. I3, FIG. I4.

c. J. FITCH.

SIGNALING SYSTEM Filed Nov. l0, 1938 3 Sheets-Sheet 3 AT'TORNEY Patented Feb. 4, A1941 UNITED STATES PATENT oFFlce .SIGNALING SYSTEM Clyde J. Fitch, Endicott, 1v. Y., assigner te mterl national Business Machines Corporation, New

York, N. Y., acorporation of New York Applieane, November 1o, 193s, serial Nu. 239,838

1,2 claims. (ci. 17a-51) 'I'his invention relates to signaling systems and more particularly to a system for operating remotely situated signaling channels in timed relationship. u

The instant application constitutes an improvement over the signaling system described in the copending application, Serial No. 756,443, filed December 7, 1934, wherein said copending application a plurality of normally non-conductivelo signaling channels are provided at a transmitting and receiving station; each channel including an electric discharge device, and wherein individual sources of fluctuating voltages are transformed into polyphase voltagesl which at each.`

i5 station are impressed upon the signaling channels for conditioning the channels periodically and cyclically at mutually exclusive intervals for control purposes. Signal initiating and indicating means are described in detail in the said V'co- 2" pending application, and are shown to control selectively. the signaling channels at the transmitting station to render them conductive upon operation of the signal initiating means for initiating code combinations of control signals which are eective to render the receiving signaling.

channels conductive in accordance with the receipt of the signals for controlling selectively the signal indicating mans. It was mentioned that individual sources of voltages are provided for 3U conditioning the signaling channels and assumed that the said remotely situated sources of voltages l are obtained from synchronous distribution systems. Y Y f It is known that for certain applicationsthat 35 such` synchronous sources oLyoltag'es are not available'and that therefore, additional provisions must be made for controlling the synchronous conditioning of the said signalingV channels. It is now proposed that the transmitting station 4o control the synchronous conditioning of the signaling channels at both stations.

To this end, certain of the available signaling channels are employed for synchronizing purposes, thus, at the transmitting station a prede-4 45 termined number of the signaling channels are normally maintained non-conductive and" disconnected from the transmission medium for signal control purposes as described in the said copending application, and that, for example, a sin- 50 gle signaling channel is connected at all times to the transmission medium so4 that, upon the periodic and cyclic conditioning of the last mentioned channel, periodic synchronizing signals are impressed continuously upon the transmis- 55 sion medium. In this manner, the normally nonconductive channels are selectively rendered conductive in accordance with the operation of the signal initiating means for initiating aperiodically timed control signals, and the selected channel. for synchronizing.control purposes is eil'ective 5 continuously for initiating periodic synchronizing signals. At the receiving station, corresponding signaling channels are provided which normally are nonconductive, and which are conditioned periodically and cyclically in synchronism 1 0 with the conditioned signaling channels at the transmitting station. Upon receipt of the timed signals, initiated upon operation of the signal initiating means, such signals are properly segregated and effective to render the corresponding l5 signaling channels conductive at the receiving station which, in turn, are eiective to control the associated signal indicating means. A corresponding synchronizing signal channel is provided at the receiving station to be responsive to the 2 0 periodic synchronizing impulses which upon re` ceipt thereof are eiiective for controlling the conditioning of the signaling channels at this station.

At each of the stations an independent iiuctu- 275 ating supply source is provided in the form of an oscillation generator adapted to produce oscilla.- tions oi a predetermined frequency. In the instant application the oscillation generators referred to are shown in the form of electronic oscillation generators, it is understood that other forms. of generatorsvof uctuating power supplies may be Aemployed ii desired. vProvision is made whereby the oscillation generators referred to are controlled and excited by the periodic synchronizing signals. Therefore, it will be seen that the synchronizing channel at the transmitting station is adapted to be conditioned by the electronic oscillation generator thereat soas to be conductive at periodic intervals to initiate synchronizing signals at such intervals and that the synchronizing signals are eiective in turn to sustain further generation of the oscillations produced by the electronic oscillation generator ythereat. Receipt of the periodic synchronizing signals at-theV receiving station is eiective to excite the oscillation generator provided thereat which in turn is then eii'ective to generate oscillations of a frequency corresponding to that of the oscillations generated Vat the transmitting station which in turn` are then impressed upon the individual signaling channels including the synchronizingchannel to condition these channels and control the conductivity thereof. It will be seen"that' the synchronizing channel is renditdered conductive periodically to sustain further generation of the oscillations at -the receiving station. In this manner, it is possible to provide a signaling system which is'self-contained and generation of the predetermined oscillations conditioning the signaling channels.

Further objects of the instant invention reside in any novel feature of construction or operation or novel combination of parts present in the embodiment-of the invention described and shown in the accompanying drawings whether within or without the scope of the appended claims and irrespective of other specific statements as to the scope of the invention contained herein. y

Inthe drawings:

Fig. 1 is a circuit diagram showing diagrammatically the circuit arrangement oi.' the signaling and synchronizing channels of the transmitting and receiving stations.

Fig. 2 shows diagrammatically one i'orm of a phase-splitting device which may be employed at the transmitting and receiving stations.

Fig. 3 shows diagrammatically the individual conductivity control means for the signaling channels at the transmitting station.

Figs. 4, 5, and 6 show various forms of impulse generators which may be employed in the present signaling system.

Figs. 7-13 show the voltage wave shapes impressed on various. sections' of the control circuits.

Fig; 14 shows graphically the 'developed phase displaced impulses representing the differential times at which the electric discharge devices at both the transmitting and receiving stations are rendered conductive.

A GENERAL DESCRIPTION Referring now to Fig. 1, the signaling System vicesare shown associated with the phase-splittingl transforming'means generally indicated by the reference characters l and lil-a which, for

the instant application, are similar in design and' shown in detail in Fig. 2. Individual sources of uctuating power are impressed upon the phasesplitting transforming means which .are effective to generate phase displaced .voltages which. in turn, arel impressed upon the associated electric The said discharge devices at both the transmitting and receiving stations are conditioned for controllingpurposes by the ilucl-l tuating powersupply periodically and cyclically at mutually exclusive intervals. -The power supplies referred to are generated by the electronic oscillation generator systems which are indicated generally in the-figure by the reference characters li and ll-a, designating the electric discharge devices and the-associated circuits which are adapted to generate oscillations of a predetermined frequency, The oscillation generator systems at both the transmitting and receiving stations are similar in design, therefore, herein, after it will be sulcient to explain in detail the circuit'arrangement and operation of only one of these systems. vThe electric discharge devices at the transmitting station are rendered conductive selectively upon operation of the signal initiating means generally indicated by the reference character l2. It is sufiicient to mention that the signal initiating means I2y may be operated singly or simultaneously in diierentcode combinations for initiating code combinations of the signaling impulses. Devices for controlling the signal initiating'means in selective combinations are well known in the art and .since these devices per se form no part of the invention; further description thereof is deemed unnecessary. However. reference may be made to the above-mentioned application or to the copending application, Se-

rial No; 113,798, filed December 2, 1936, wherein methods of conditioning and controlling" the signallng initiating means is shown -and described in detail.

It is to be noted that normally the signal initiating means I2 maintain the electric discharge devices T-I to T-B disconnected from thetransmitting circuit arrangementl whereas the synchronizing channel including the electric discharge device T-8 is at all times connected thereto for impressing continuously thereon the periodic synchronizing impulses. It is also to be noted that the synchronizing channel is eiective at all times to impress the initiatedv periodic synchronizing signals upon the associated oscillation generator generally designated by the reference character i I, in this manner, sustaining further generation of the oscillations which in turn are effective for controlling the conditioning of the signaling channels. y

At the receiving station the devices.R-I to R6 are rendered conductive in accordance with the control signals received for controlling the energization' of the signal indicating control means indicated generally by the reference character i3. Such signal indicating means controlled by the single or combinations of signals are well known in the art, and need not be disclosed in detail; however, reference is made to the above mentioned copending application or the copending. application Serial No. 178,016, led Y .December 4, 1937, wherein methods of conditioning and controlling signal indicating means are shown and described indetail. The synchronizing channel at the receiving station including the electric discharge device R--8 is controlled continuously at periodic intervals bythe received synchronizing signals for controlling the ener-.

gization or .excitation of the associated oscillation generator generally indicated by the reference character il'-'a.I The oscillations generated thereby are of the same frequency as the generated oscillations at the transmitting station, and are in synchronism therewith so'that when the said oscillations are impressed upon the signaling channels at the receiving station these, channels are conditioned periodically and cyclically at the same intervals that the corresponding channels of the transmitting station are conditioned.- Thus, it will be seen that the initiated periodic synchronizing signals are effective to control the excitation of the oscillation generators `at both stations, in this manner mainand receiving stations.

taining synchronous operation of the oscillation generators and, of course, in turn maintaining synchronous conditioning and operation of the associated signaling channels of the .transmitting Phase transforming means Referring now to4 Fig. 2, the phase transforming means associated with the signaling channels which may be employed at both the transmitting and receiving stations will now be del scribed. Y

,being the same. It is to be noted that the turns ratio of some of the individual secondary windings vary so that the voltages across thesaid windings vary accordingly. For example, the secondary windings associated with the primary winding I4 comprises twowindings I4-a and III-d of voltages E and four windings .UI-h,

I4-c, I 4-i-e, I4-f of voltages equal to l/n/ E.

'I'he secondary windings I5-a to I5-f asso-- ciated with the primary winding I5 are'similarly rated'and therefore when connected as shown in the figure, the output voltages of the connected secondary windings are all of equal Y values. It is evident from the description thus ferred to as a duplex diode triode type.

far, and from the circuit arrangement shown in the gure, thatfour different phases, equally spaced electrically, namely, forty-five degrees apart, are developed. The phase directions vectorially are shown by the arrows foreach of the phases in the said gure. It is to be noted that eight secondary outputs are providedl and for this reason, the output circuits of the secondary windings are arranged in pairs. Thus, two circuits each are provided upon which the same phases arev impressed, such as the circuits indicated by the designations, phase I and phase 5, or thosev designated phase 3 and phase 1. The purpose of this. arrangement will be understood as the description progresses.

Channel conductivity controlling means Referring now to Figs. 4, 5, and 6? the operationof an individual electric discharge device nected to any one of the secondary output circuits of the said phase transforming means will now bev described, and is shown to comprise an electric. discharge device T equivalent to a full Wave rectifier and-triode in one envelope and which is well known in the art, commonly re- The diode plates 20 are joinedfto the terminals of any one of the said secondarywindings of the phase transforming means, in the example chosen, indicated at I4-a,. thecenter tap of which is connected to the grid control element 22 of the, device T, and bymeans of the resistor L23 is also joined to the cathode element 24 thereof. It is evident from thisdescription that normally the grid element of the device is at zero bias, since no current is impressed upon resistor 23, therefore, upon closure of the signal device and the associated cathode.

initiating means shown as the 'tonta'cts l2, a. momentary current iiow is established in the triode plate circuit as follows: From the positive terminal of the battery a to the resistor b, anode and cathode elements of the device T, to the negative terminal o f the said battery. This described condition exists in the circuit for only'a comparatively short time because the bias of grid 22 remains no longer at zero value, and is not a constant factor but varies in a tmedrelationship with the frequency -of the fluctuating supply source. The said supply source by means of the windings I 4-a is impressed upon. the full wave rectifier section of the device .and the rectified voltage impressed upon resistor 23 immediately drives the grid bias negative with respect to the cathode. The value of the resistor 23 is adjusted so that before the grid bias becomes effective to reduce the plate current' to substantially zero value, a pulse is impressed upon the output circuit just traced so that a short signal impulse is impressed'upon the outpt circuit associated with the resistor b. It is 'understood now that as the signal initiating means I2 is maintained in an operative position the device T is rendered conductive periodically so that a series of short equally spaced impulses will be continuously impressed upon the said output circuit and-that the frequency ofL the initiating signals is twice the frequency of the iiuctuatingvsupply source. vReferring to Figs. '7-9 the voltage wave forms impressed upon different sections of the circuit are shown; Fig. 7 represents the sinusoidal Wave lshape of the voltage impulses impressed upon the diode plates 20 of the device; Fig. 8 represents the rectified wave forms impressed on the resistor 23, and the wave form shown in Fig. 9 represents theimpulses gener- -at'ed and impressed upon'the output circuit of the devices each time the said device is rendered conductive which as described is at those times' that the said voltage supply passes through zero value.

Referring now to Fig. 5, the electric discharge device T and the associated circuits are shown similarly arranged as shown and described in connection with Fig. 4 with the exception of the additional provision of the condenser 24 connected between one of the diode plates 20 of the It is evident now from the description just set forth that the grid element 22 of the device is at zero bias when the fluctuating supply impressed in the secondary winding I4-a passes through vzero due to the fact'that no current is passing through the resistor 23. It is at such periods thatthe device is conditioned toA be conductive thereby permitting' current to flow in the associated output l circuit. The effect of the condenser 24 as shown in Fig. 5 will now be described. When the polarity is suh that current passes from the diode ode, this current passes through the resistor 23 Vplate 20 connected to the condenser 24 to cathand also charges the condenser 24 to the po- -larity as shown. At the end of this particular half cycle as the current passes'through zero, thecharge in the condenser maintains the grid `of the device negative with respect to the cathode and is of such value as to be sufficient to permit noplate current to flow. The charge in the condenser leaks on" through the resistor 23, the value of the capacitor and resistor being such that the time constant of the circuit is adjusted so as to maintain the device non-conductiveI during the timed interval that the said zero, and during part of the following half cycle until the 'current passing from the other diode p1ate'f20 to the capacitor and through resistor 23 has reached suiiicient amplitude'to maintain thedevice biased so as to be maintained nonconduc'tive. At the end of the second half cycle the charge in condenser 24 has completely leaked off, and as thesaid halfk cycle passes through zero the grid bias is zero thereby permitting the deviceto be rendered conductive momentarily.

Thus, it is seen, that during the transition period during the iirst and second half cycle, the device is continuously rendered non-conductive,

ancl'during the transition period between thesecond .and third half cycles, the condenser having received no charge during Athe sec-A ond half' cycle, or if I'any charge, is in the opposite phase thereby having no effect upon the bias and thus permitting the device to, be conductive as the fluctuating supply voltage passes through zero. The curve shown in Fig. 10 shows the wave shapes of the rectified voltage across the resistor 23 in the circuit arrangement shown in Fig. 5. The effect of the condenser 24 is evident, namely, suppressing the alternate .peaks of the rectified Waves as shown, and as just explained, the suppressed waves are eRective to maintain the bias of the device such sov as to render the device non-conductive, Whereas the 'unsuppressed waves are effective to render the device conductive. VThus it is seen, that the device is rendered conductive one time for each complete cycle of theuctuating power supply impressed thereupon, whereas without the condenser the said device wouldA be rendered conductive twotimes during a complete cycle of a fluctuating power supply.V

In Fig. '11, the impulses indicated therein are representative of lthe periods at which the device shown in Fig. 5 is rendered conductive and the shortl current impulses flowing in the output circuit ofthe device at such times, which is seen from the ligure, occurs at equally spaced timed intervals. Now assume that the condenser 25 is connected in the diode plate circuit opposite to that shown in Fig. 5. for example, as shown in Fig. 6, between the cathode and the other diode plate 20. With the condenser inserted in the circuit as shown in Fig. 6 it is obvious that the opposite peaks of the rectiiied wave forms will be suppressed and render the tube non-conductive. In Figs. 12 and 13 the wave forms are shown when the condenser 24 is included in the circuit as it is shown in Fig. 6. It is seen that the opposite peaks of the rectiiied waves are suppressed to render the device non-conductive at those particular intervals. The impulses represented in Figs. 11 and 13 indicate comparatively the timed intervals during which the device T is rendered conductive depending upon which diode plate circuit the condenser 24 is inserted therein.

It is now understood that by inserting the condensers-in the opposite legs of the diode plate circuits and impressing fluctuating supply sources which are in phase, or ofthe same phase, upon the discharge devices that two different and separate signal generating circuits are obtained for initiating two series of equally spaced impulses,`

`phase transforming means l0 designated phase 1 tophase' 8. It is noted that the condensers 24 associated with the devices T-I to T-i are connected in one leg of the individual diode 'plate circuits thereof and for the devices T-5 to^T8 are connected in the opposite legs of the diode plate circuits. It was mentioned that pairs of v similar or like phases of the voltage sources are developed, for example, phases 1 and 5 are shown vectorially to be in the same direction. Therefore, by connecting .the individual electric discharge devices and the associated circuits as described to the individual secondary output circuit .of the phase transforming means for example to phases 1 and 5 and having the condensers 24 connected in the opposite legs of .the diode plate circuits as shown, it is understood that the devices T--l and T-5 are rendered conductiveat such intervals to initiate series' of control impulses diametrically opposite in phase, that is, electrical degrees apart, as shown in Fig. 14.

Thus, it will be understood without further detailed description, that with the four different phases developed 'by the phase transforming means and a twin or double set of secondary circuits, and by connecting lthe electric dischargeI devices` and the associated circuits thereto, and connecting .the condensers 24 inversely in the twin secondary circuits, that eight separate siglnal generating circuits are obtained to generate eight differently timed signal pulses for control purposes, said pulses being spaced or separated 45. electrically. s

4VThe signal initiating means l2 are shown connected tothe anodes of the devices T-l to T-l and the common conductor 25, so that upon operation thereofv the associated devices are rendered conductive to initiate the timed signal impulses and effect energization of thel following circuit at the various timed intervals; from thev positive terminal of the power supply designated C, to the conductor 25, anodes and cathodes of the devices T-'l to T-'l, conductors 26 and 2l, coil 20 to the negative terminal of thesaid power supply.

It is seen that the anode element of the device T-8 is connected directly to the conductor 25 so that whenever the said device is conditioned by the voltage source impressed .thereon by means of the secondary output circuit designated phase 8, the said device is rendered conductive at periodic intervals continuously thereby permitting current to ow in the following circuit: from the positive terminal of Ithe power supply C, to conductor 25, anode and cathode elements of device T-0, conductor 29, resistor 30, conductor 21 and coil 28 to th'e negative terminal of the said supply C. In the event that all the signal initiating means I2 are closed at the same time for initiating the control impulses, the arrangement of the pulses as viewed by a cathoderay oscillo- The oscillation generators shown in Figs. l, and employed in the transmitting and receiving circuits are similar to the oscillator circuit fully shown and described in detail in the copending application Serial No. 100,070, fi-led September 10, 1936. Therefore, the following brief description 2,2%,6'79 of the oscillation vgenerator circuits employed in the instant application is deemed suflicient. 'I'he operation of the oscillation generator circuit .employed in the receiving circuit arrangement is identical to the operation of the generator in .the

transmitting circuit arrangement which will now be described.'

y -that the control tube Il is normally biased and conditioned soy that no plate lcurrent is flowing in the output circuit thereof. Connected .to the plate of -tube YIl is a tuned circuit arrangement `comprising capacitance 33 and inductance 3d.

The primary Winding of the transformer 32 is connected in shunt relationship toresistor 30.

^ Assuming, now for the moment .that periodic control impulses are impressed upon the resistor 30 and are of such value as to overcome the bias o f tube Il, thereby permitting, whenever the pulses are impressed upon the resistor 30, current to through the tuned circuit causes excitation thereflow from the positive terminal ofthe potential source designated D through the said tuned circuit arrangement to the'anode'and cathode elements of the vtube Il to the negative terminal of the sai-d source. 'Ihe current `iiow established ofat a frequency 'depending upon the LC constants of the oscillatory circuit. The oscillatory circuit just described is shown coupled to any suitable amplifier and lter arrangement generally designated .by the reference character 35 by means of the coupling condenser 35 and resistors' 31 and 38, so that the oscillations generated by the said tuned circuit are impressedl upon the amplifier and filter arrangement through the said coupling condenserpand resistors. The coupling means, just referred to, which is inserted between the .tuned4 cir-cuit and the input of theampliiierarrangement 35 also is suitable as a phase shifting means. Different adjustments of the .phase shifting may be effected and varied slightly by means of adjusting `the resistor 38 referred to. The gener-ated oscillations are then amplified by any sui-table arrangement designated 35 which may also incorporate a suitable filter which is used merely for the purpose of filtering out the higher harmonics in delivering a pure sine wave the output of ,the filter. The amplified oscillations are then impressed upon the phase transforming means I il which as described hereinabove is then effective to transform the voltage input into a multi-phase voltage supply source. For further descriptive details of this oscillation circuit, reference may be made to the last-mentioned copending application.

Transmitting circuit arrangement Referring now to Fig. 1, the operation of the .signal generating and transmitting circuits will nowbe understood.

The individual signaling channels including the electric discharge devices T-- to T-B are connected to the individual output circuits of the 4phase transforming means l0, several circuits of which are shown in detail in Fig. l. The signal initiating means I2 included in the individual signaling channels are connected in common to the conductor 25 and the individual plates of the devices T--I to T-G. As mentioned hereinabove, the signal initiating means I 2 may be, operated singly or in different code combinations by the mechanisms referred to in the 'first-mentioned copending application for controlling theconductivity of the individual signaling channels associated therewith. Upon operation of any of the signal initiating means I2 equally spaced time signals will be initiated. The timing of the outof-phase controlsignals with respect to each other is controlled by the phase displaced voltages impressed upon the input circuits of the electric discharge devices. The signaling channels just referred to relate to those associated with phases 1 to 6 of .the phase transforming means I 0. In

..Fig. 1, phase? is not shown to be included in the transmitting and receiving circuits.' This phase maybe usedv for other `controlling purposes not relevant to'l the present invention. Phase 8 of the phase transforming means l0 shown connectedto a signaling channel which will be referred to hereinafter as the synchronizing control channel and is shown to include the electric discharge device. '1l-8, is shown to be connected directly to the common conductor 25. The cathode element ofthe device T- 8 is connected by means of the conductor 29 to one terminal of the resistor 30.- The cathode elements of the devices T-l to T-B are connected in common by the conductor 2B tothe other terminal of Ithe said resistor and also by means of the'conductor'l is extended to an output circuit comprising the control tube 39 and outputtransformer 40. The control tube 39 is adapted to be biased so that normally noplate current is owing in the output circuit thereof including the primary Winding of the :transformer 40.

Assume now, that the control switch il is closed and thatthe signal initiating means 25 remain unoperated for the moment, current flow is immediately established through the synchronizing control channel as follows: from the positive terminal of supply source'g, through conductor 25 to the anode and cathode elements of the device T-8, conductor 29, resistor 3B, conductor 2l, coil 28 to the negative terminal of the said source. This momentary fiow of current is effective to reduce the grid bias impressed upon the controltube 39 so that current flow is now established in the output circuit thereof as follows: from the positive terminal of the potential supply source E, through the tuned circuit arrangement including the primary Winding of transformer 40 to the anode and cathode elements of the said tube to the negativek terminal of the said supply source, thus, impressing upon the transmission medium generally designated t2 associated with the secondary winding of the transformer 40- a control signal which will be identified as the synchronizing control signal. 'Ihe voltage drop across the resistor 3@ is also effective tol reduce the. grid bias of the tube il of the oscillatorcircuit permittingl this tube in turn to be conductive and as described hereinbefore excite the associated tuned circuit arrangement comprising the condenser 33 and the inductance 34 to initiate oscillations of a predetermined frequency which arethen, ln turn,

- impressed upon the amplifier arrangement 35 and voltage impressed upon the said device passes through zero and due to the insertion of the condenser 24 Yin one legr of the diode plate circuit thereof, the device T-8 is rendered conductive only one time foreach complete cycle of the voltage supply. Immediately upon building up of the voltage supply source `by means of the excited oscillator generator circuit, impulses are generated by the synchronizing channel including the device T-ii at the rate of one impulse for each cycle, which impulses are then impressed upon the resistor 30 for periodically controlling the operation of the oscillator control'tube II which, in turn, controls the excitation of the associated tuned circuit thereby sustaining further generatiori of the oscillations which are'impressed upon the phase transforming meansland, secondly, for controlling the conductivity of the control tube 39 thereby impressing periodically synchronizing control signals upon the transmission medium 42 associated with the secondary winding of the transformer 40. In this manner, it is seen that `the synchronizing channel is rendered conductive periodically for continuously control-v ling the excitation of the oscillator circuit and for continuously impressing periodically at intervals synchronizing impulses upon the transmission medium. The generated oscillations which 'areimpressed'upon the phase transforming means I0 are effective to control the conditioning of the signalingchannels including the devices T-I to T-$ for controlling the conductivity of these channels whenever the signaling initiating means I2 associated therewith are operated. It was mentioned hereinabove that theV signal initiating means I2 may be operated either singly-or in various code combinations to render theassociated signaling channels conductiveto initiate at periodic intervals the variably timed control signals;

Itis seen that upon operation .ofthe signal initiating means I2, thevarious character signals are impressed-upon the common conductor 26 and'upon the conductor 21 to control the conductivity of the control tube 39 which, in turn, is

' effective toimpress control signals upon the out- Aso put transformer 40 and theA connected transmission medium 42. The circuits controlled by the control signals initiated 'by the signaling and synchronizing channels will now be described.

Receiving circuit arrangement Referring now to Fig. 1; the operation of the 'receiving circuitY will Vbe described briefly. The individual -receiving signaling channels including the'electric discharge devices R-I to R-S A and the synchronizing channel including the device R-B are shown connectedto the individual output circuits of the phasetransforming means Ill-a, several circuits of which are shown in detail. The said phase transforming means corresponds exactly to the phase transforming means Il) and is adapted by means of the polyphase voltages developed .thereby to control the conditioning of the connected circuits including the devices R-I to R-.8 in exactly thesame manner as the devices T-I to T-B are conditioned for controlling the conductivity thereof,

therefore it is deemed unnecessary to repeat this description Vat this time.

The plates ofthe triode elements of the devices R-Ito Rf-8 are connected in common to thev conductor 43 and the cathode element-oi the control tube 44, the 'grid element offwhich isr shown connected to the secondary winding of the receivingtransformer 45 and a suitable source of negative potential so that normally this tube is biased to be -non-conductive during the intervals that no signals are impressed upon the transmission-medium 42 which lis shown conthe associated tubes A--I to A--6.

manner maintain the signal indicating control means I3 deenergized until such times when the particular control signals are received and impressed upon the receiving circuit arrangement. As mentioned hereinbefore, the signal indicating control means may be controlled singly or in various code combinations.

Now assume that at'the transmitting station, the sv'vitclil l4I is closed and the signal initiating means I2 remain unoperated so that the devices T-I to T--G remain ,nonconductive, it is understood that a plurality of periodic synchronizing impulses are initiated by the synchronizing channel including the device T-Bfa'nd im.- pressed upon the transmission medium 42.

The synchronizing signals received at the-receiving station are then impressed upon the control tube 44 to render this tube conductive whenever -the said signals are impressed upon the grid element thereof. synchronizing impulse received the tube 44 is rendered conductive momentarily permi ting current to flow through the following circ 'tz from the positive terminal ofthe potential source F, anode and cathode elements of tubel 44, conductor 46, anode and cathode elements of the triode section of the device R- (at this moment the grid'element thereof is a zero bias, thus permitting the device to be conductive), conductor 41, resistor 48,v conductor 49, coil 50, and conductor 5I to the negative terminal of the said source. Energization of the resistor 48 is effective to overcome the grid bias o n .the oscillator control tube II-abdue to the voltage drop across the said resistor which is impressedupon the grid element of the oscillator control tube by means of the transformer 52. The control tube II---a` is rendered conductive momentarily to excite the associated tuned circuit ar-A rangement comprising the capacitance y53 and It is now,seen -that for each' inductance 54. The generated oscillations, the

frequency of which is adapted to be the same as the frequency of the oscillations generated at the transmitting station, are then impressed upon the filter :and amplifying arrangement generally designated 55 by mea'ns of the coupling condenser 56 and resistors 5l, and in turn, are then impressed upon the input circuit of the phase transforming means IIL-a. It is understood now, that immediately upon impressing the oscillations upon the phase transforming means, the device R-B is conditioned so as to be non'- conductive except at those periods when the voltage impressed' upon the said device passes through zero and due to the insertion of the `condenser 24-11 in the` one leg of the diode plate circuit thereof, the device R-8 is rendered conductive only one time for each complete cycle of the voltage supply. Immediately upon building up of the voltage supply source by means of the excited oscillator generator circuit, impulses are generated by the synchronizing channel including the device R- at the rate of one impulse for each cycle, which impulses are then impressed upon the resistor I8 for periodically controlling the operation ot the oscillator control tube lI-a which in turn, controls the excitation of the associated tunedv circuit@r thereby sustaining further generation of the oscillations which are impressed upon the phase transforming means. The operation of the synchronizing and oscillator circuits just described is.exactly. the same as the operation of the synchronizing and oscillator circuits employed at the transmitting station and described in detail hereinabove.

It is evident'now that the synchronizing and oscillator circuits at both stations are operated in exact synchronisrn. The reason for this is obvious, since the periodic synchronizing signals initiated at theV transmitting station control the periodic operation of the oscillator circuits at both staions. It also follows' that the devices T8 and R-8 included in the synchronizing channels are rendered conductive at the same intervals since the voltages impressed upon the individual circuits are of the same phase, or stated in otherV words, are in phase. The impulses developed in Fig. 14 for phase 8 represent the periodic intervals at which the devices T-B and R-B are rendered conductive. The frequency at which these devices are rendered conductivedepends solely upon the predetermined frequency oi the oscillations generated by the described oscillator circuits.

It should be .mentioned that upon initial conditioning of the receiving circuits, that is, upon conditioning the system with the synchronizing signals, before initiation of the character signals, that as soon-V as the rst synchronizing signal is impressed upon the receiving circuit arrangement not only is the synchronizing channel rendered conductive momentarily, but similarly are the other signaling channels associatedF with,

phases 1 to 6 and including the devices R-I to R-E. However, the individual signal receiving channels can be so arranged that the momentary period of conductivity of these channels effects no faulty operation of the associated signal indi-- eating control means. This can be eected by selecting the capacity of elements C-I toC-S to be of such value so that a predetermined numl ber of received impulses are necessary before-the individual capacity elements are eective to discharge and overcome the individual grid bias impressed upon the grid control elements ofthe tubes A-i to A-. It is' 'seen that immediately upon receipt of the iirst synchronizing impulses that the power supply is instantly generated by the oscillator circuit arrangement and impressed upon the phase transforming means so that control of the signal receiving channels is immediately, established; and since the synchronizing signals are the only signals being received at this time and since the channel including the device Y Rf-- is the only channel in phase with the incoming synchronizing signals, consequently re. ceipt of these signals is no longer eective to render the remaining signaling channels conductive.

In .order to describe briey how the individual signaling channels may be rendered conductive for signaling control purposes assume that the signal initiating means l2 at the transmitting station associated with the signaling channel including the deviceT--i is operated thereby ini-- tiating a series -ofparticularly timed impulsesV vwhich are impressed upon the transmission medium. It is understood that'the character signals initiated and generated.l thereby are impressed upon the transmission medium in addition to the periodically timed synchronizing impulses which are continuously gneratedby the synchronizing channel including the device T-8. The contin-l uously initiated synchronizing impulses are effective at all times tocontrol the synchronizing channel at the receiver thereby controlling the generation of the power supply thereat which is .impressed upon the phase transforming means and which in turn is eilectivel to control'the segregation oi' the timed character signals which are initiated and generated aperiodically upon operation'of the diierent signal initialing means I2. Continuing now with the example, the'character signals generated by the signaling channel including'the device v'1II are impressed upon the signal. receiving means to render thev control tube 44 conductive, at these particular intervals,

thus permitting current to ow in the following.

circuit: from the positive terminal of the potential source F, to anode and cathode elements of tube 44, conductor 46, anode and cathode elements of device R-i condenser C-I and^resistor L-l to the negative terminal of the said source. Upon energization of the described circuit by the series ofcharacter impulses impressed thereon,

the condenser C-I is charged by a predetermined number of the said series of impulses; which charge leaks ci through the resistor L-I impressing a relatively long continuous impulse on the grid .of tube A-I, reducing the bias on the grid element thereby rendering the tube conductive and permitting current to ow in the output circuit of tube A-l including the signal indicating control means I3. It is seen that the said signal indicating control means is energized as long as the signal initiating means I2 associated with the device T-i is operated. Itis understood from the description just set forth that the remaining signaling channels including the devices R-2 to R- are not rendered conductive at the time that the character sign'als are received which. are generated by the signal initiating means associated with the iirst'signaling channel including the device 'l2- i.

It is evident now that the conditioning of the remaining simg channels including the said devices R- to R-S is such thatv these remaining lchannels are not adapted to be rendered conductive at the same timed intervals the said character signals, initiated by the device 'IL-l,

are received. It is seen that'the signaling channel, at the receiving station, associated with the output circuit oi7 phase 1 of the phase trans--V forming means .isconditioned so that the conductivity of this channel is controlled in synchronism with the conditioning of the signaling channel associated with the output circuit of phase 1 of the phase transforming means at the transmitting station. Similarly the .signaling channels at the receiver associated with the remaining phases 2 Vto 8 ofthe phase transformchannels occurs at mutually exclusive timed intervals. It is evident then that the individual signaling channels at the receiving station associated with thejdiiierent phase output circuits are adapted to be responsive solely to the signals initiated by the individual transmitting signaling channels associated with the output circuits of the corresponding phases of the phase transforming means vat the transmitting station.

It is seen, therefore, that the periodic and continuous initiation of the timed synchronizing signals are effective to'control the energization of the controlling oscillationgenerators at both the transmitting and receiving stations,` which oscillations are effective tocontrol the'synchronous conditioning of the signaling channels at both stations, whereby, the sig alingchannel controlling means can be operate singlypr in various code combinations for initiating timed character signals which, in turn, are segregated by the signaling channelsf at the receiver and als upon segregation thereof the said receiving signaling channels are rendered conductive to control the associated indicating control means* accordingly.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied'to a single modication it will be understood that various omissions and substitutions and changes in" the form anddetails oi' the device illustrated and in. itsoperation may be made by those skilled inpthe art without departing from the spirit of the inven- 1 tion. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A signaling system comprising a transmitting and receiving station, a series of normally non-conductive signaling channels at both sta' tions, means comprising an oscillation generating system' for conditioning each of the said series of channels periodically and cyclically at mutually exclusive intervals to control the conductivity of the individual channels, means cooperating with the said channelsA at thetransmitting station for rendering the channels conductive to initiate both aperiodic 'and periodic control signals, means responsive to the periodic signals for vcontrolling the said oscillation generating systems for sustaining further operation thereof for conditioning the associated channels, and means cooperating with the series of channels at the receiving station responsive to the aperiodic signals for segregating the signals including means for-rendering the corresponding channels conductive for control purposes.

2. A signaling system comprising a transmitting and receiving station, a series of normally non-conductive signaling channels at both stations, means comprising an electron tube oscillator system for generating oscillations of aA predeterminedvfrequency including means for utilizing the oscillations for conditioning each of the said series of channels periodically and cyclically at mutually exclusive intervals to control the conductivity of the individual channels,

means cooperating with the said channels at the transmitting station for rendering the chan` nels conductive to initiate both aperiodicandperiodic control signals, means responsive to the periodic signals for controlling the electron tube oscillator systems for sustaining further operation thereof for conditioning the associated 7s channels, and means cooperating with the series of channels at the receiving Vstation responsive to the aperiodic signals for segregating the signals including means for rendering -the -cor responding channels conductive for control purposes.

3. Asignaling system comprising a transmitting and receiving station, a series of signaling channels at both stations, each channel including a normally` non-conductive electric discharge device, means comprising an electron tube oscillatorr system for generating oscillations of a predetermined frequency including means for utilizing the oscillations for conditioning each o f said series of channels periodically and cyclically at mutually exclusive intervals to control the `conductivity of the associated discharge devices, means cooperating with the said channels at the transmitting station for rendering the associated' devices conductive to initiate both laperodic and periodic control signals, means responsive to the periodic signals forcontrolling the said oscillator systems for sustaining further operation thereof for conditioning the associated channels and devices, and means cooperating with the series of channels at the receiving station responsive to the' aperiodic signals for segregating the signals including means for rendering the corresponding devices conductive for control purposes.

4. A signaling system comprising -a transmitting and receiving station, a series of normally non-conductive signaling channels at each station, means comprising oscillation generating controlling the said oscillation generating systems for sustaining further operation thereof for conditioning the associated channels, and means cooperating with the series of channels conditioned at the receiving station responsive to the aperiodic control signals for segregating the signals-including means for rendering the corresponding channels conductive for control purposes.

5. A signaling system comprising a transmitting and receiving station, a plurality of normallynon-conductive signaling channels at each station and means at each station comprising means forv generating a power )supply for conditioning' the signaling channels thereat periodicalv ly and cyclically at mutually exclusive intervals for controlling the conductivity thereof, means for rendering the channels at the receiving station conductive aperiodically for initiating control signals, a synchronizing control channel at each station, means for rendering the last mentioned channel conductive for continuously .transmitting a series of synchronizing signals, means 'at the transmitting station responsive to the syncnronizing signals including means for controlling the power supply generating means thereat to sustain further operation of the generating means, means at the receiving station responsive to the synchronizing signals including means for Y rendering the synchronizing control channel thereat conductive; means controlled by the last mentioned channel for controlling the associated power supply generating meansl at the receiving station to sustain further operation thereof, and means responsive to the said aperiodic signals including means for rendering the conditioned channels at the receiving station conductive in accordance with the signals.

6. A signaling system comprising a transmitting and a receiving station, a plurality of normally non-conductive signaling channels at each station and means at each stationfor conditioning the said signaling channels thereat periodically and cyclically at mutually exclusive intervals for controlling the conductivity thereof, means at the transmitting station for rendering the channels conductive aperiodically and selectively to initiate control signals, means at the receiving station responsive to the control signals including meansfor rendering certain of the con-A ditioned channels thereat conductive in accordance with the signals, means at the transmitting station for initiating synchronizing signals and individual means at both stations controlled by the synchronizing signals including means for conductivity thereof, means at the transmitting' station for rendering the channels conductive thereat including means for initiating. controlV signals whenever the channels are rendered conductive, means at the receiving station responsive to the signals for rendering the conditioned chan- 45 is thereat conductiveincluding means for segregating the signals for control purposes, means at the transmitting station for initiating synchronizing signals, and individual means at both stations controlled by the synchronizing signals including means for controlling the corresponding fluctuating power supply generating means to sustain further operation thereof and conditioning of the associated channels.

17. A signaling system comprising a plurality of normally non-conductive signaling channels, means for conditioning the channels periodically and cyclically for controlling the conductivity thereof, means for rendering certain of the channels conductive aperiodioally including means for initiating control signals when the said channels are rendered conductive, means for` rendering another of said channels conductive continuously at periodic intervals for initiating synchronizing signals, and means responsive to the synchronizing signals including means for controlling the channel conditioning means.

9. A signaling system comprising a plurality of normally non-conductive signaling channels. means for generating a fiuctuating power supply including means for utilizing the said supply for conditioning the channels periodically and cyclically for controlling the conductivity thereof,means for rendering certain of the 'channels conductive aperlodically including means for initiating control signals when the said channels are rendered conductive, means for rendering- `receiving station impressing the signals upon signaling channels thereat which are conditioned cyclically, periodically and in synchronism with' the incoming signals for segregating them, utilizing the control signals at the receiving station for control purposes, and utilizing the synchronizing signals at both stations for controlling' the condition of the associated signaling channels thereat.

11. The method of signaling which comprises conditioning signaling and synchronizing channels at transmitting and receiving stations pe riodically and cyclically at mutually exclusive intervals thereby controlling the conductivity thereof, and at the transmitting station rendering the signaling channels conductive selective- `ly and aperiodically for initiating control signals and the synchronizing channel conductive periodically for initiating' synchronizing signals, utilizing the control signals for rendering the signaling channels at the receiving station conductive for segregating the said signals for ,con-

trol purposes, and utilizing the synchronizing signals rst at the transmitting station for controlling the conditioning of the said channels thereat and second at the receiving station for rendering the synchronizing channel thereat conductive for controlling the conditioning of the said channels thereat.

12. The method of signaling which comprises conditioning a plurality of normally non-conductive signaling and synchronizing channels at a station periodically and cyclically for controlling the conductivity thereof, rendering the signaling channels conductive for initiating timed control signals aperiodically for control purposes and rendering the synchronizing channel conductive for initiating timed synchronizing signais periodically, and utilizing the synchronizing signals Vthereat for controlling the conditioning of the said channels.

CLYDE J. FITCH. 

